I have a possible way for you. I don't know if it is how you wanted it but if not just write what's wrong and i can fix it for you. If you have any questions write them to me and not in this conversation.
command /playergroups <player>:
trigger:
set {Adminsuuid} to "%uuid of arg-1%"
set {playername} to "%arg-1%"
add "%arg-1%" to {alladmins}
send "Added %{playername}% to adminlist" to player
send "UUID ofplayer: %{Adminsuuid}%" to player
add arg 1 to {Admins::*}
command /adminlist:
trigger:
send "Admins: %{Admins::*}%" to player
command /remove <player>:
trigger:
set {Adminsuuid} to ""
remove arg 1 from {Admins::*}
send "Removed %arg-1% from adminlist" to player
